Characterization of Carbon Black Filled PDMS-Composite Membranes for Sensor Applications

摘要

This paper describes the characterization of conductive PDMS (CPDMS) composites. Composite have been achieved by filling the PDMS with CarbonBlack (CB). Two different methods were used to prepare the CPDMS composites: (A) direct mixing of CB with PDMS (CB-PDMS); (B) dissolving of CB in methanol before mixing with PDMS (CB-Methanol-PDMS). At a certain critical CB concentration, called percolation threshold, the membranes get conductive. Membranes of CPDMS (thickness ~ 100μm) have been fabricated. CPDMS membranes of method (B) show a smoother surface profile as membranes of method (A). By means of a two-point resistivity measurement, the electrical resistance of CPDMS membranes was measured. With an increase of the CB concentration, the resistance decreases. Membranes of method (B) show a low percolation threshold and a low surface resistivity. Effects of pressure and temperature on the membrane resistance were investigated, too. Around the percolation threshold, the resistance shows the highest sensitivity on pressure and temperature variations. The Young's modulus of CPDMS membranes exponentially increase with an increase of the CB concentration.